Environmental Sustainability in the Demolition and Construction of Viaducts

This thesis explores the environmental impact of the demolition and construction of viaducts using a Life Cycle Assessment (LCA) approach with the aim of proposing a framework for decision-makers and engineers to reduce the emissions related to construction and demolition projects, contributing to the development of more sustainable and durable infrastructures. The analysis examines all stages of the structure's life cycle from material extraction, construction, service life, and maintenance to end-of-life disposal. Particular focus is placed on the carbon footprint generated throughout these phases which is measured in terms of CO2 equivalent (CO2e) emissions since it represents the most significant parameter adopted in literature and provides a conversion criterion starting from all other relevant Greenhouse Gases (GHG). By Identifying the most important processes such as material production, transport and waste management, this study reveals that material choice, recycling potential and construction methods play key roles in determining the overall environmental impact. In addition, this report suggests various strategies to manage GHG emissions, such as adopting low-carbon and recycled materials, optimising structural design to reduce resource consumption, and implementing more sustainable demolition techniques to maximise material recovery and recycling with a view to the circular economy perspective. Analysing the case study of demolition of an existing viaduct and its subsequent new construction this thesis provides practical insights for reducing GHG emissions and promoting sustainable construction practices within the context of large-scale infrastructure projects. A comparison between different construction materials is performed with an in-depth analysis of the adoption of Glass Fibre Reinforced Polymer (GFRP) instead of traditional steel rebars, focusing on the energy required for its production beyond the related CO2e emissions.